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6 Sheets-Sheet 1.

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`T'. HERALD.

STEAM BOILER.

No. 535,525. Patented Mer. 26, 1895.

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T. HERALD.

STEAM BOILER. Y No. 536,523. Patented Mar. 26, 1895.

Mimes d1 h I laren/01: l J4/Mw www (No Model.) 6 sheets-sheet 3.

T.HBRAL D. STEAM BOILER.

NO.- 536,523. Patented Mar. 26, 1895.

(No Model.) 6 Sheets-Sheet 4.

T.. HBR-ALD.

STEAM BUILER.

No. 536,523. y Patented Mar. 26, k1895.-

6 sheets-smet 6.

(No Model.)

'I'. HERALD. STEAM BoILBR.

yPatenized Mar. 26, 1895.

im: aims vzrzRs co., PHOTaLrrHo.. WASHINGTON. u. c.

NITnaD STATI-LsA PATENT OFFICE.

THOMAS HERALD, OF DUNDEE, SCOTLAND.

STEAM-BOILER.

SPECIFICATION forming part Of Letters Patent No. 536,523, dated March 26, 1895.

Application nlea my 1s, 1394.

.To all whom t may concern,..-

Beit known that I, THOMAS HERALD, a subject of the Queen of Great Britain and Ireland, residing at 18 St. Andrew Street, Dundee, in the county of Forfar, Scotland, United Kingdom of Great Britain and Ireland, have invented Improvements in Steam-Boilers, ofl

which the following is a specification.

This invention has reference to improvements in steam boilers of the Water tube type and is designed to provide boilers of this kind possessing all the advantages of Vsteam boilers of the ordinary marine type without their disadvantages, and wherein the tube ends and tube plates are so disposed asto be away from the Zones of the most intense heat.

In order that the nature of my invention may be fully understood, I will proceed to eX- plain the same by aid of the accompanying illustrative drawings, in which- Figure 1 is a central longitudinal section of a water tube boiler constructed according thereto. Figs. 2 and 3 are'vertical cross sections thereof on the lines II Il and IIIIII respectively of Fig. 1. Fig. 4 is a corresponding section to Fig. 3 showing a modified arrangement. Fig. 5 illustrates in section devices for putting the heating tubes individually out of action when desired. Figs. 6, 7, 8 and 9 illustrate respectively two methods of arranging the outermost or shell tubes and securing them to their tube plates, Figs. 6 and 8 being sections, and Figs. 7and 9 corresponding plans.

The water tube boiler' shown in Figs. 1, 2 and 3, comprises an upper longitudinal steam and water vessel 1 connected with four longitudinal lower watervessels 2, 2b, 2c and 2d, between which the lire grates 3 are placed, by. heating tubes 4, 4a to 17, 17, these heating tubes being so bent and arranged as to form at the front end of the boiler three furnace chambers 18, 181 'and 18 having close roofs, with a return ue 19 above them, and at the rear end, a combustion chamber 2O that isv somewhat similar to that of an ordinary marine boiler. The front of the boiler risprovided with a smoke box 21 in connection with the return flue 19, and the frontv of the 'f'urnace chambers 18a, 18, and 1SC is closed by a metal or other suitable furnace front 22 provided with fire doors 23. The back-of the seria No. 517,912. (No man per water and steam vessel 1 (hereinafter called a separator), and with the lower water vessels 2, 2b, 2c and 2d; or the back of the -boiler maybe formed by a series of tubes connecting the separator with the longitudinal Water vessels 2 2d, or with a transverse water chamber fitted between the said longitudinal vessels, the interstices between the tubes being filled with suitable refractory material.

The separator 1 is preferably made of cylindrical form as shown', and provided withv projecting wings 25 and 25b each having preferably fiat sides 26 and 27, of which the lower one, viz., 26, form tube plates to which the upper ends of the heating tubes 4 to 17a are secured in any suitable or convenient way, as by screwing or expanding, or in the manner hereinafter described with referencev to Figs. 6, 7, 8 and 9, while the other or cover plates 27 are provided with holes which are normally closed by stoppers 27 and corresp'ond to the holes for the tubes in theopposite tube plate 26, so that access can be readily obtained for fixing and cleaning'the tubes. The interior of the lseparator 1 is connected with the interiors of the wings 25 and 25b by a series of holes 1a that serve to provide ample passage for steam and Water to pass separately from the corresponding wing to the separator so that the steam will not tend to .take up any of the water and the holes will not materially reduce the strength of the separator. between the cover plates 27and the tube plates 26 in which the holes 1a are formed, should besuitably strengthened to resist liability of their being flattened by reason of the tangential stress to which they are subjected, due to the internal pressure on the tube and cover plates 2b' and 27; or the separator, instead of being made ot' circular form in cross section as shown in Figs. 1, 2 and 3, may be made of a form resembling` an oval in cross section, its upper cylindrical portion Having a smaller radius than ils lower cylindrical portion. y

The longitudinal water vessels 2a, 2b, 2c and 2d which may be connected with oneanother by horizontal stay tubes 28, are preferably The side portions of the separator',4

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also made with flat sides 29 and 30 like the separator wings 25a and 25".

The heating tubes 16, 16a, 17, and 17a forming the outermost, or two outermost rows of tubes on each side of the boiler, are brought close together or made to touch one another after leaving the tube plates 26 and 29 of t-he separator wings and water vessels respectively, so as to form the sides or shell of the boiler. These tubes may advantageously be fixed in place by screwing a ferrule or gland 17* into each of them from the insides of the tube plates 26 and 29 to which they are to be connected, in which case the ends ot' the said tubes may be enlarged as shown in Figs. 6 and 7, so that the internal diameter of the ferrules or gland 17* may be equal to the effective internal diameter of the tubes into which they are screwed. In this case the tubes where they are secured to the tube plates are arranged in two rows. The tubes may however be secured to the tube plates in a single row as shown in Figs. 8 and 9 with reference to the tubes 1G, which are then made of the` same diameter throughout and secured by screw ferrules or glands 16* similar to 17*. In this case the tubes are rendered more effective as struts or stays, but their eective internal diameter is reduced by the ferrules orglands.

The other or inner tubes 4, 4n to 15, 15a forming the sides and crowns of the furnace chambers 18, 18" and 18c and the return flue 19, rise from the water vessels 2at 2d (Fig. 2) on each side of each furnace chamber, cross over the latter toward the opposite side of the boiler, and then with one or more bends, pass to one of the separator wings.

The two sets of tubes rising respectively from the two sides of each furnace chamber diverge from each other at their intermediate portions so thattheir surfaces will be more fully exposed to the llames and heated gases than their end portions; and where a series of tubes cross the corresponding one from the other side of a furnace chamber, diaphragms 31 of in etal or other refractory material are arranged and extend, where necessary, to the water vessels 2a 2d, thus separating the furnace chambers 18, 18",18c from each other and from the return flue 19 above.

These diaphragms, which in the example` shown, are carried by the tubes 4 and 14; 6 and 12 and 8 and 10 for the furnace chambers 18, 18" and 18C respectively, mayconveniently be formed of tire-clay tiles suitably shaped and fitted together, semi-circular recesses being formed in theirabutting surfaces, where necessary, to permit of the passage as shown ofthe other heating tubes into the furnace chambers.

Filling blocks 19a are placed where, owing tothe curvature ot' the sinuous heating tubes, large openings or passages, not traversed by tubes, are formed between the combustion chamber and the uptake 2l.

In the arrangement shown in Figs. 1, 2 and 3, the heating tubes 4 to 15 form two main groups arranged to cross each other so as to form the three furnace chambers 18a, 18" and 18c one group consisting of the tubes 4, 4a to 9, 9iL and the other of the tubes 10, 10a to 15, 15a. Each group thus comprises twelve lon gitudinal series of tubes which are so bent and arranged that near their junction with the wings and water vessels they form six longitudinal rows of tubes composed in the one group of the tubes 4 and 4 to 9 and 9EL and in the other group of the tubes 10 and 10 to 15 and 15a, while their intermediate portions form twelve rows of tubes composed in the one group ot' the tubes 4, 4 to 9, 9a and in the other of the ltubes 10, 10El 15, 15, the tubes in each row being spaced apart in consequence of the crossing of the two groups.

The several sets of tubes having their axes in parallel vertical planes, viz: sets composed of the tubes 4 to 9, 4a to 9, 10 to 15 and 10n to l5a may be arranged so close together as to touch each other where they cross. It is preferred however to leave a space ct equal in width to the diameter of one of the tubes between each set of tubes 4 to 9 and the adjacent set 10 to 15 and between each set 4a to 9 and the adjacent set 10 to 15, as by this means it is practicable, by removinga shell tube 16, 16, 17 or 17a opposite such a space, the lateral filling block 19 adjacent to such shell tube, and a portion of the corresponding diaphragm or diaphragme 31 to take out and replace any tube without disturbing the others.

The combustion chamber 2O may advantageously be provided with a series of heating tubes 32, 32", 32, and 32d (see Fig. 3), which rise from the water vessels 2, 2", 2, and 2d respectively and pass alternately to the right and lett sides of the boiler and thence to the separator wings, some, as shown, or all of such tubes, passing under the cylindrical lower portion of the separator l so as to protect the same to som extent from direct impact of the flame.

When more than one combustion chamber is required, the divisions between them may be formed by rows of tubes as shown in Fig.

4, which shows three combustion chambers...

In this case there are two divisions, one formed by someof the tubes 32'"L and 32c and the other by some of the tubes 32" and 32d, such tubes being brought near together or made to touch one another along their vertical portions. Other rows ot' tubes, composed of the remaining tubes 32, 32", 32c and 32d extend upward through the said chambers but cross each other at the top and bottom as shown. Whether one or more combustion chambers be formed, the spaces between the crossing tubes at the bottom thereof, are preferably filled with refractory material, and the spaces at the `top may be wholly or partially so treated.

At the front of the boiler, two strong stay tubes 33 may be fixed between the separator IOO IZO

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serving to hold parts of 'the boiler firmly together, and also as downtake tubes to convey water from the separator to the said water vessels. Each of the stay tubes 33 may have one or more short horizontal tubes passed through it, so that the comparatively large diameter of the stay tube will not prevent the return ue 19 from being readilycleaned. The stay tubes 33 may, if desired, be replaced by one or more simple struts. In some cases, as in land boilers, the stay tube or tubes, or

-strut or struts, may be dispensed with.

When a boiler according to my invention is constructed to be fired from both ends, the vertical water chamber 24: will be centrally situated between the two combustion chambers, or it may be omitted, the combustion chamber or chambers being then made common to one or more furnaces from each end.

To enable any one of thel heating tubes 4: 17a to be readily put out of action when necessary, I provide opposite each of the open -ends of each tube, a stopping device capable of being operated from the exterior of lthe wing or water vessel to which the end of the tube is connected, so that it can be forced against, so as to eftectually close, the end of the tube. Two stopping devices suitable for this purpose are shown in Fig. 5, one being in its operative position and the other in its inoperative position. Each comprises a plug or stopper 34 carried by a screw threaded spindle 35 so asto be rotatable' thereon. The screw spindle 35 [its in a screw plug 36 fitted in each cleaning hole in the cover plates 27 or 30 opposite the tube plates 26 or 29 of each of the Wings 25a and 25b and water vessels 2a 2d, a washer 37 of suitable material, for example lead, being iitted to each side of the plug or stopper 34: so that thelatter can be caused to make a tight joint with the screw `plug 36 when in its inoperative position as shown to the right of Fig. 5, and with the end of the heating tube say l1, when moved into its operative position as shown at the left of the said figure, at which time a screw cap 88 is screwed over the outwardly projecting end of the spindle so as to form with the aid of awasher'39, a fluid tight joint with the outer side of the screw plug 36 and thus prevent leakage of steam between the screw threads of the spindle 35 and screw plug 36.

A stopping device of the kind mentioned may be used in water tube boilers of various constructions for the purpose specified.

The boiler is mounted on suitable seats 40, preferably of sufficient height to render the under side of the longitudinal water vessels 2' 2d readily accessible and which form ash pits underneath the iire-grates. It is also provided with a suitable casing and withthe usual aids to safe and convenient working.

It is obvious that the constructions hereinbefore set forth may be variously modified.

For example, instead of a single separator 1, two or 'more separators may be used, and

the shape of the separator may be modified by changing the inclination or position and shape ofthe wings. In some cases the wings may be dispensed with, the` upper ends of the tubes being then bent round and secured to the cylindrical portion of the separator.-

Again, the number of water vessels may be varied according to the number of furnace chambers required, and instead of being of rectangular form in cross section, they may be of other form, for example circular. In this case, access for fixing and cleaning the tubes may be obtained through cleaning holes formed in the vessels opposite the tube ends.

The number of rows of heating tubes and t-he number of tubes in each lrow may be increased or diminished according to circumstances. In the example shown, the holesin thetube plates in which the heating tubes are secured are pitched longitudinally and transversely so that lines passingthrough their centers will be at right angles to each other, but the holes may obviously be pitched in a diagonal manner so that a greater number of tubes can be secured in a'given area of tube plate than with the previous arrangement, when this is desirable. In this case the tubes would be bent alternately forward and rearward to bring them into parallel rows or sets, so that those belonging to one group may cross those belonging to the other group.

It will also be obvious that access can be obtained to the separator wings and water vessels otherwise than through the cleaning holes, as for example by removing the plates yopposite to those in which the tubes are secured; also that the flue 19 may be divided by suitable diaphragms of refractory material,

into several flues corresponding to the several combustion chambers when such are used.

What I rclaim isl. A Water tube boilercomprising an upper longitudinal separator, lower longitudinal water vessels, and inner andouter groups of heating tubes connecting the same, said heating tubes being arranged to' form at the front end of the boiler one or more furnace chambers having close roofs anda return flue or iiues located ymainly below said separator and above but out of communication with said furnace 'chamber or chambers except at the ends' thereof, and at the rear end of the boiler one or more enlarged combustion chambers connecting the rear ends of said furnace'chamber or chambers and flue or lues'substantially as herein described.

2. In a water tube boiler, the combination with an upper separator, lower water vessels, and an outer shell or casing,.of inner bent heating tubes, connecting said separator and water vessels along part onlyl of their length so as to leave an enlarged combustion chamber at'the rear end of said boiler, said heating tubes being arranged to cross each other and form one or more furnace chambers having close roofs and one or 'more return flues located mainly below said separator and above IIO but not in communication with said furnace chamber or chambers except through said combustion chamber, substantially as herein described.

3. A water tube boiler comprising an upper longitudinal separator, lower longitudinal water vessels, two main groups of heating tubes connecting said separator and water vessels for a part only of their length and arranged to cross each other and form one or more furnace chambers and one or more return flues, and refractory material applied to the portions of tubes forming thereof of said chamber or chambers so as to separate said chambers from said fines throughout their length, and an outer shell or casing inclosing said heating tubes and forming with the separator rear end of the boiler and rear ends of said groups of heating tubes, a rear combustion chamber substantially as herein described.

4. In a water tube boiler, the combination with an upper separator'V and lower water vessels, of two main groups of tubes connecting said separator and water vessels and arranged in parallel rows or sets, the rows or sets in one group being arranged to alternate with and cross those in the other group and to form therewith one or more furnace chambers and one or more return dues, refractory material applied to the said tubes so as to separate said chamber or chambers from said return ue or ues throughout their length, a combustion chamber at the rear ends of said chamber or chambers and return fine or lines substantially as herein described.

5. In a water tube boiler, the combination with a separator, Water vessels, and outer groups of tubes connecting the same and forming the shell or casing of the boiler, of two main inner groups of tubes also connecting said separator with said water vessels and arranged in parallel rows or sets, said rows or sets of tubes being arranged in pairs each consisting of a row .or set from each group and separated from adjacent pairs by a space at. least equal in width to the diameter of one of said tubes substantially as herein described for the purpose specified.

6. In a water tube boiler, the combination with an upper separator and lower water Vessels, of two groups of tubes each having their upper ends connected with saidseparatorand their lower ends with said water vessels, the lower portions of one group being arranged to form one side and part roof of two or more furnace chambers, and the lower portions of the other group being arranged to form the remaining side and part roof of said furnace chambers, substantially as herein described.

7. In a Water tube boiler, the combination with an upper separator and lower water vessels, of two groups ot sinuous tubes arranged to cross and recross each other one group having its upper ends connected with the right hand side of said separator and its lower ends with the water vessel or vessels located at the right hand side of one or more furnaces and the other group having its upper ends connected with the left hand side of said separator and its lower ends with the water vessel or vessels located at the left hand side of the said furnace or furnaces substantially as herein described. i l

8. A water tube boiler comprising an upper separator, lower water vessels, an outer shell or casing, inner bent heating tubes connected with said separator and water vessels along a part only of their length and arranged to form one or more furnace chambers and one or more return dues, an enlarged combustion chamber located at the rear of said bent heating tubes, and supplementary heating tubes located within said combustion chamber and connected with said separator and water vessels substantially as herein described.

9. A Water tube boiler comprising an upper separator, lower water vessels, an outer shell or casing, inner bent heating tubes connected with said separator and water vessels along a part only of their length and arranged to form one or more furnace chambers and one or more return flues, an enlarged combustion chamber located at the rearof said bent heating tubes, and supplementary heating tubes located within said combustion chamber and connected with said separator and Water vessels some of said supplementary tubes being arranged to form one or more Walls or partitions dividing said combustion chamber into two or more smaller combustion chambers substantially as herein described.

` lO. A water tube boiler comprising an upper separator provided with one or more wings in communication therewith, lower water Vessels located at opposite sides of one or more furnace chambers, an outer shell or casing and two main groups of heating tubes arranged to cross each other and form at the front end of the boiler, one or more furnace chambers and one or more return lines located below said separator and above said furnace chamber or chambers, and at the rear end of the boiler a combustion chamber substantially as herein described.

ll. A water tube boiler comprising an upper separator provided with one or more wings, lower water Vessels, and heating tubes connecting said water chambers with said Wing or wings, the interior of said wing or each of said wings being placed in communication with the interior of said separator by two or more holes or passages arranged at different levels to admit of water and steam entering the separator in separate streams, substantially as herein described for the purpose specified.

IIO

l2. A water tube boilercomprisingan upper separator provided with one or more wings each having at opposite sides lower water vessels located at opposite sides of one or more furnace chambers and also each having fiat opposite sides, and two groups of bent heating wings with the upper sides of said water vessels, said inner groups of sinuous tubes being arranged to cross each other and form several furnace chambers between said watervessels and a return tlue above said chambers, an enlarged combustion chamber located between the outer groups of tubes and at the rear ends of said furnace chambers and return flue, a

smoke box at the front end of said returniue, refractory filling material applied to the portions of tubes forming the roofs of said furnace chambers and filling blocks located in the spaces where the curvature of said heating tubes leave large passages unobsiructedby tubes between said combustion chamberand uptake substantially as hereinl described for the purpose specified.

14. In a water tube boiler the combination with the heating tubes connecting the upper separator with lower water Vessels, of stopping devices arranged opposite the open ends of each tube and each comprising a plug or stop provided on opposite sideswith washers of elastic or yielding material, a screw threaded spindle extending through a screw plug fitted in a hole in the plate opposite the tube plate carrying the tube to be stopped so that said spindle can be operated from the exterior ot` said boiler', and a screw cap adapted to be screwed over the outwardly projecting end of said spindle and to form a Huid tight joint with the outer side of said screw plug substantially as herein described t'or the purpose specified.

In testimony .whereof I have signed my name to this specification in the presence of two subscribing witnesses.

THOMAS HERALD. Witnesses:

WM. CROWLEY, ALFRED MACKENZIE,

Both of 81 Murmg/gate, Dundee. 

